Fairly roundabout way of doing things, but I'm glad we got what we wanted in the end. I guess they succeeded in making their free users aware of other paid options e.g. Office365
I didn't play chicken, I signed up to their discounted Workspace plan for my three user domain. The process of switching to a non-business legacy account was very smooth - can be accomplished through a chatbot on the admin portal.
Edit: Slight technicality, I'm still on a Workspace plan, but won't be charged for it, and they may remove business-level support in future. This is different being on a non-business legacy plan. For one, it appears I get 30GB of storage per user rather than 15GB